If a mixture of two liquids, neither of which is miscible or soluble in the other, is vigorously stirred or shaken, an emulsion—defined as a fine dispersion of minute droplets of one of the liquids in the other—may form. A transmissive liquid lens encloses two immiscible fluids, one polar and one non-polar, each characterized by a different index of refraction, within a housing. The housing incorporates electrodes by which the shape of the liquid lens, and therefore its optical power, may be manipulated based on the principles of electro-wetting. If such a lens is subjected to impact or shock loads, for example due to the impact of the lens or a device including the lens being dropped, large accelerations may occur, resulting in localized pressure drops within the lens, which may in turn cause the liquids to emulsify. Factors thought to play significant roles in determining whether emulsification will occur in response to localized pressure drops include the magnitudes of the acceleration-induced local body forces, liquid flow parameters, vapor pressures, and surface tension. In some cases, cavitation may even occur, increasing the likelihood of emulsification. In any event, the formation of an emulsion in a liquid lens is deeply undesirable, as it will negatively impact the optical performance of the lens.
It is therefore desirable to provide a method for preventing the formation of an emulsion in a liquid lens in response to an impact or shock load.